Differential mortality risk of postprocedural creatine kinase-MB elevation following successful versus unsuccessful stent procedures.

OBJECTIVES

This study was designed to evaluate the effect of periprocedural myocardial infarction (MI) on mortality according to success of the stent procedure.

BACKGROUND

The mortality effect of periprocedural MI relative to successful versus unsuccessful procedures has not been examined.

METHODS

All-cause mortality during the first year was evaluated prospectively among 5,850 patients from coronary stent clinical trials. Myocardial infarction was classified according to creatine kinase-MB level as type 1 (>1 but <3 times normal), type 2 (>or=3 but <or=8 times normal), or type 3 (>8 times normal or Q-wave MI). Procedures were classified as successful unless there was a final diameter stenosis >50%; final Thrombolysis In Myocardial Infarction flow grade <3; final National Heart, Lung, and Blood Institute dissection grade >or=D; repeat revascularization within 24 h; or stent thrombosis within 24 h.

RESULTS

Myocardial infarction was more frequent after unsuccessful procedures (69.6% vs. 20.4%, p < 0.001). Mortality during the first year was higher in patients with MI (2.8% vs. 1.7%, p = 0.01), but the effect was significant only for type 3 MI (4.7% vs. 1.7%, p = 0.008). Moreover, the mortality difference for any MI was confined to patients with unsuccessful procedures (13.1% vs. 0%, p = 0.03), with no significant effect among patients with otherwise successful procedures (2.1% vs. 1.7%, p > 0.20). The independent predictors of mortality were unsuccessful procedure (p < 0.001), diabetes mellitus (p = 0.001), history of prior MI (p = 0.003), multivessel disease (p = 0.006), and advancing age (p < 0.001), but not periprocedural MI.

CONCLUSIONS

The association of periprocedural MI with increased mortality during the first year following stent placement was confined to patients with unsuccessful procedures.